IPv4 Problems

An Overview

The number of users on the Internet is continuely increasing very fast, but the address
structure of the IPv4-header is fixed. In its later years, this is leading to
problems as the number of free addresses is becoming less and less.
Another aspect is that with the development of new applications
like Multi-Media and video conferencing, new features of IP are needed. The
following points should demonstrate why a new IP is being developed:

The increase of the number of users of the Internet means that IP
addresses are running out. IP supports only a fixed 32 bit field for
addressing.

IP addresses have only a 3 level hierarchy. IP supports only the three
hierarchies: net, subnet and host.

The granularity of IP address allocation is too gross. In IP you have only
four classes of nets: Class A, B, C and D (a fifth class, class E, is only
for research purposes). These classes differ in the
number of nets and hosts:

Class A

125 nets - about 16 mill. hosts per net

Class B

16382 nets - 65534 hosts per net

Class C

about 2 mill. nets - 254 hosts per net

Class D

multicast network class

In addition to that, new features are needed as well, ie:

Provider selection.
You can choose special providers for routing the packet.
This is necessary for commercial usage of the internet, making it
possible to choose only special providers i.e. trusted providers.

Scalable multicast.
Multicast in IP is only possible in subnets. For Multimedia-applications
it should be possible to address different hosts in different
subnets.

Mobility. "plug-and-play"
Mobility means that you can plug in a host to the net with no need to
configure it by yourself and others can
address it and reach it. This would mean that your host would have to get
an address from a provider.

Real-time flow.
That feature is important for real time services like video conferences
etc...